Characteristics of the Japanese Diet Described in Epidemiologic Publications: A Qualitative Systematic Review

Abstract

Summary Context: International interest in the Japanese diet has grown in recent years. Objective: The aim of this systematic review was to evaluate and organize the Japanese diet and dietary characteristics from an epidemiological perspective, mainly focusing on the nutritional and dietary elements. Data Sources: PubMed, Web of Science, Japan Medical Abstracts Society, JDream III, and CiNii databases were searched. Study Selection: The eligibility criteria included research with an epidemiological study design that was either crosssectional, cohort, or case-control-based that defined the dietary patterns of the Japanese diet using dietary pattern analysis. A total of 39 research articles that described the Japanese diet were included. Data Extraction: The data that were extracted included the following: implementing country, location, study design, participant characteristics, key outcomes, methods used in the analysis of dietary patterns, and descriptions of the Japanese diet. Data Synthesis: As a result of the systematic review analyzing the descriptions of the Japanese diet from 39 selected articles, we were able to aggregate the descriptions into 16 categories from 33 factors. After performing a content analysis using a further aggregation of categories, we found that the top three applicable categories were soybeans/soybean-derived products, seafood, and vegetables; these were followed by rice and miso soup. Conclusion: The Japanese dietary content was found to be diverse based on an examination of epidemiological studies; however, we were able to aggregate the content into 16 categories. The Japanese diet is considered to be a dietary pattern that contains a combination of factors: the dietary staple, side dishes, and soup.

A cross-sectional study of the associations between the traditional Japanese diet and nutrient intakes: the NILS-LSA project

“…Second, referring to a recent review [15], we defined a 12-component modified Japanese Diet Index (mJDI 12 ) to which 3 adhering components ("soybeans and soybean foods", "fruit", and "mushrooms") had been added to the JDI. Thus, the mJDI 12 score ranged from 0 to 12.…”

“…Additionally, as well as the above 9 components of the JDI, a recent systematic review has reported that several other foods, in particular, "soybeans and soybean foods", "fruit", and "mushrooms", could also be applied as components of the traditional Japanese diet [15]. Therefore, there is also a need to examine the nutritional characteristics of a modified JDI that includes these 3 components.…”

The Possibility of Suppression of Increased Postprandial Blood Glucose Levels by Gamma-Polyglutamic Acid-Rich Natto in the Early Phase after Eating: A Randomized Crossover Pilot Study

“…Japan has one of the longest life expectancies worldwide [1], and the traditional Japanese diet has attracted attention as a factor supporting the health and longevity of people in Japan [2]. Natto, the soybeans fermented by strains of Bacillus subtilis, is a frequently consumed traditional food in Japan [3], and the health benefits of its consumption, such as reduced risk of death from ischemic stroke [4] and improved bone strength [5], as well as reduced risk of hypertension with the consumption of natto and miso [6], have been suggested in epidemiological research.…”

Intake frequency of vegetables or seafoods negatively correlates with disease activity of rheumatoid arthritis

“…Especially, there has been an increasing interest in the Japanese diet, which is rich in fishes and vegetables. Epidemiological studies focusing on the Japanese diet have been difficult because of the vast variation in Japanese foods [9], although the association between the Japanese diet and lower insulin resistance was reported [10]. There have been few reports in Japan on the association of dietary habits with disease activity and the numbers of patients in those reports were small [11,12].…”